BGDA Practical Placenta - Placental Functions
Practical 14: Implantation and Early Placentation | Villi Development | Maternal Decidua | Cord Development | Placental Functions | Diagnostic Techniques | Abnormalities |
Term Placenta
Increase in placental weight by birth gestational age GA.
Placenta Vasculature - MRI and CT
Term placenta viewed from the fetal side.[1]
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Magnetic Resonance Angiography (MRA) | Computed Tomography Angiography (CTA) |
Legend
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Exchange
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- oxygen, carbon dioxide, carbon monoxide
- nutrients
- water, glucose, vitamins
- electrolytes
- waste products
- urea, uric acid, bilirubin.
- hormones
- mainly steroid, protein hormones poorly transported.
- maternal thyroid hormone can slowly cross.
- fetal insulin can impact on maternal diabetes.
- maternal antibodies
- maternal IgG antibodies are transferred from about week 13 GA across the placenta
- from the maternal lacunae syncytiotrophoblast cell endosomes bind IgG through neonatal Fc receptors.
- drugs and their metabolites
- pre-existing maternal conditions
- illegal drugs (fetal drug addiction)
- infectious agents
- cytomegalovirus, rubella, measles, malaria, listeria, microorganisms
Endocrine
Protein and steroid hormones.
- Human chorionic gonadotrophin (hCG) - like leutenizing hormone, supports corpus luteum in ovary, pregnant state rather than menstrual, maternal urine in some pregnancy testing
- Human chorionic somatommotropin (hCS) - or placental lactogen stimulate (maternal) mammary development
- rise through pregnancy, stimulates maternal metabolic processes, breast growth
- Human chorionic thyrotropin (hCT)
- Human chorionic corticotropin (hCACTH)
- Relaxin
- Steroid Hormones - progesterone (maintains pregnancy), estrogens (fetal adrenal/placenta)
Placental Estrogen
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Fetal adrenal cortex produces dehydroepiandrosterone sulphate (DHEA-S) that is converted by the placenta into estrogens[2][3] Placental estrogen, mainly estriol, suppresses gonadotropin secretion from the maternal pituitary gland. Maternal estrogen levels are often a useful indicator of fetal well being.
A second role for fetal adrenal DHEA-S is possible regulation of the effects of glucocorticoids on the developing brain.[5] |
Placental Metabolism
Synthesises - glycogen, cholesterol, fatty acids
- provides nutrient and energy
Placental Functions Interactive Component
Attempt the Quiz - Placental Functions | ||
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![]() Here are a few simple Quiz questions that relate to Placental Functions from the practical.
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Practical 14: Implantation and Early Placentation | Villi Development | Maternal Decidua | Cord Development | Placental Functions | Diagnostic Techniques | Abnormalities |
Additional Information
Additional Information - Content shown under this heading is not part of the material covered in this class. It is provided for those students who would like to know about some concepts or current research in topics related to the current class page. |
- ↑ Rasmussen AS, Lauridsen H, Laustsen C, Jensen BG, Pedersen SF, Uhrenholt L, Boel LW, Uldbjerg N, Wang T & Pedersen M. (2010). High-resolution ex vivo magnetic resonance angiography: a feasibility study on biological and medical tissues. BMC Physiol. , 10, 3. PMID: 20226038 DOI.
- ↑ Rainey WE, Rehman KS & Carr BR. (2004). The human fetal adrenal: making adrenal androgens for placental estrogens. Semin. Reprod. Med. , 22, 327-36. PMID: 15635500 DOI.
- ↑ Parker CR. (1999). Dehydroepiandrosterone and dehydroepiandrosterone sulfate production in the human adrenal during development and aging. Steroids , 64, 640-7. PMID: 10503722
- ↑ Albrecht ED & Pepe GJ. (2010). Estrogen regulation of placental angiogenesis and fetal ovarian development during primate pregnancy. Int. J. Dev. Biol. , 54, 397-408. PMID: 19876841 DOI.
- ↑ Quinn TA, Ratnayake U, Dickinson H, Castillo-Melendez M & Walker DW. (2016). The feto-placental unit, and potential roles of dehydroepiandrosterone (DHEA) in prenatal and postnatal brain development: A re-examination using the spiny mouse. J. Steroid Biochem. Mol. Biol. , 160, 204-13. PMID: 26485665 DOI.
Drugs
The placenta and fetal tissues may deal with drugs differently from adult target tissues. In particular, drugs are "cleared", metabolised and excreted, at a different rate in both the fetus and in newborn infants. In general there is a much lower rate of clearance.
Adam MP, Polifka JE & Friedman JM. (2011). Evolving knowledge of the teratogenicity of medications in human pregnancy. Am J Med Genet C Semin Med Genet , 157C, 175-82. PMID: 21766440 DOI.
van Gelder MM, Roeleveld N & Nordeng H. (2011). Exposure to non-steroidal anti-inflammatory drugs during pregnancy and the risk of selected birth defects: a prospective cohort study. PLoS ONE , 6, e22174. PMID: 21789231 DOI.
Salisbury AL, Ponder KL, Padbury JF & Lester BM. (2009). Fetal effects of psychoactive drugs. Clin Perinatol , 36, 595-619. PMID: 19732616 DOI.
Practical 14: Implantation and Early Placentation | Villi Development | Maternal Decidua | Cord Development | Placental Functions | Diagnostic Techniques | Abnormalities |